This application focuses upon human ovarian cell-cell regulatory mechanisms of a biochemical nature and involves experimentation with human granulosa cells derived from in vitro fertilization (IVF) procedures. The work scope will emphasize the physiological effects of growth factors and of putative autocrine/paracrine factors produced by the cells themselves upon cellular growth and differentiation in vitro. Specific aims are: 1) to separate and characterize granulosa cell sub-types according to density, morphology, mitotic activity, reproductive hormone (gonadotropin, estradiol) receptor distribution or function, and steroidogenesis in serum-free and serum-containing medium, 2) to characterize in detail a progenitor cell sub-type which is mitotically active under serum-free conditions, and 3) to investigate whether certain growth factors are selectively produced by specific granulosa cell sub-types under serum-free conditions. The long term goal of this research is to provide information about endocrine-dependent cell-cell regulatory mechanisms such as growth factor-gonadotropin interactions within the human ovary which will be applicable to clinically significant problems such as ovulatory disorders and cystic conditions. This work should provide new concepts with which to understand the basis of these disorders.